From 6fea20e5611fc5c8264f04a878a98c06b6209eed Mon Sep 17 00:00:00 2001 From: Xuan Zhuo Date: Mon, 1 Aug 2022 14:38:36 +0800 Subject: virtio_ring: split: introduce virtqueue_resize_split() virtio ring split supports resize. Only after the new vring is successfully allocated based on the new num, we will release the old vring. In any case, an error is returned, indicating that the vring still points to the old vring. In the case of an error, re-initialize(virtqueue_reinit_split()) the virtqueue to ensure that the vring can be used. Signed-off-by: Xuan Zhuo Acked-by: Jason Wang Message-Id: <20220801063902.129329-17-xuanzhuo@linux.alibaba.com> Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_ring.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'drivers/virtio') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 8cbb19cdb1ce..1852912d711e 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -220,6 +220,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index, void (*callback)(struct virtqueue *), const char *name); static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num); +static void vring_free(struct virtqueue *_vq); /* * Helpers. @@ -1114,6 +1115,39 @@ static struct virtqueue *vring_create_virtqueue_split( return vq; } +static int virtqueue_resize_split(struct virtqueue *_vq, u32 num) +{ + struct vring_virtqueue_split vring_split = {}; + struct vring_virtqueue *vq = to_vvq(_vq); + struct virtio_device *vdev = _vq->vdev; + int err; + + err = vring_alloc_queue_split(&vring_split, vdev, num, + vq->split.vring_align, + vq->split.may_reduce_num); + if (err) + goto err; + + err = vring_alloc_state_extra_split(&vring_split); + if (err) + goto err_state_extra; + + vring_free(&vq->vq); + + virtqueue_vring_init_split(&vring_split, vq); + + virtqueue_init(vq, vring_split.vring.num); + virtqueue_vring_attach_split(vq, &vring_split); + + return 0; + +err_state_extra: + vring_free_split(&vring_split, vdev); +err: + virtqueue_reinit_split(vq); + return -ENOMEM; +} + /* * Packed ring specific functions - *_packed(). -- cgit v1.2.3